The reason I like the Santa Maria degli Angeli e dei Martiri basilica so much is because I never could have guessed the secrets it held on the inside from its unusual façade, an almost forbidding minimalist curved brick wall with large bronze doors. But once you walk inside and pass the small antechamber, you enter an enormous, airy horizontal nave. The reason for its unusual shape is because the church was built within the structure of the Baths of Diocletian which were the largest bath structures in the city – so when you walk around the main chamber you are walking above the old “tepidarium” (a warm sauna-like room in an ancient Roman bath). The church was designed by Michelangelo and in his style the inside is very voluminous; many churches make visitors feel small but this one has particularly gigantic proportions.
Santa Maria degli Angeli e dei Martiri is not only important for its unique architecture but also for two astronomical elements within it. There is an elaborate sundial, made of bronze and marble, situated to the right of the main chamber. Inaugurated by Pope Clement XI in 1702, it was created to determine the exact date of Easter Sunday each year. The sundial features beautiful signs of the zodiac on either side of the line. The church also has the only boreal meridian in the world which was used as a solar clock to track the pole star and the equinox until the mid-19th century.